Albert Schweitzer was a renowned 20th century German physician on Earth.
The name "Schweitzer" was the first name chosen by The Doctor in his attempts to create an identity for himself. Kes suggested that The Doctor choose a name before going on his "first away mission" (in the holodeck) as it "might help [him] feel more like a Starfleet officer". The Doctor first used the name when introducing himself to the holo-character Freya. He later renounced the name to Captain Janeway, saying that "the last time I heard that name spoken was a painful one… I don't think I want to be reminded." (VOY: "Heroes and Demons")
Nevertheless, The Doctor still considered the name in a discussion with Kes, among other names such as Pyong Ko, Jarvik and Pasteur. (VOY: "Fury")
According to the Star Trek Encyclopedia, 3rd ed., p. 432, Albert Schweitzer (1875-1965) was a theologian, musician, and medical doctor. He spent part of his life working at a missionary hospital and was the winner of the 1952 Nobel Prize for Peace.